Toronto researchers are challenging a longstanding belief about the mind and, in the process, suggesting there is additional hope for people who have lost many of their personal memories after a devastating brain injury.

The researchers have concluded that people with such memory loss can still read other people's feelings and intentions — they can still detect sarcasm or deception, for example — abilities necessary for social relationships.

"It's encouraging to know that this ability may be more resilient and preserved in us than was first thought," neuropsychologist Shayna Rosenbaum of the Baycrest Centre's Rotman Research Institute said in a release Thursday.

The scientists, from the Baycrest institute and York University, tested the assumption that humans rely on their personal recollections, called episodic memory, to make sense of other people's behaviour. This "theory of mind" is widely accepted in scientific circles.

In the experiment, two individuals, known as K.C. and M.L., had lost their personal memories in motorcycle and cycling accidents. But when tested on detecting empathy, deception and sarcasm in others, they did as well as 14 healthy subjects.

"We found that if you're trying to put yourself mentally in someone else's shoes, you don't need to put yourself in your own shoes first," Rosenbaum said.

She suggested the individuals' ability to infer other people's feelings and intentions may be related to their knowledge of general facts about the world and people — what is called semantic memory — which was not disrupted by the injury.

The research was published in the journal Science on Thursday.